(19)
(11) EP 1 215 910 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
10.09.2003 Bulletin 2003/37

(43) Date of publication A2:
19.06.2002 Bulletin 2002/25

(21) Application number: 01310113.4

(22) Date of filing: 03.12.2001
(51) International Patent Classification (IPC)7H04N 7/26, G06T 1/00
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 07.12.2000 GB 0029850
31.08.2001 GB 0121197

(71) Applicant: SONY UNITED KINGDOM LIMITED
Weybridge KT13 0XW (GB)

(72) Inventors:
  • Pelly, Jason Charles
    Reading, Berkshire RG6 4DU (GB)
  • Keating, Stephen Mark
    Reading, Berkshire RG6 3AB (GB)

(74) Representative: Pratt, Richard Wilson et al
D. Young & Co, 21 New Fetter Lane
London EC4A 1DA
London EC4A 1DA (GB)

   


(54) Watermarking


(57) Material is represented by transform coefficients represented by digital numbers. A method of perceptibly watermarking the material comprises the steps of: changing representations of the said numbers according to an invertible algorithm without changing the number of bits in the said numbers; and encoding the changed n bit numbers to effect compression encoding of the material.





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